Railcar couplers are disposed at each end of a railway car to enable joining one end of such railway car to an adjacently disposed end of another railway car. The engageable portions of each of these couplers is known in the railway art as a knuckle. For example, railway freight car coupler knuckles are taught in U.S. Pat. Nos. 4,024,958; 4,206,849; 4,605,133; and 5,582,307.
Knuckle failure accounts for about 100,000 train separations a year, or about 275 separations per day. Most of these separations occur when the train is out of a maintenance area. In such cases, a replacement knuckle, which can weigh about 80 pounds, must be carried from the locomotive at least some of the length of the train, which may be up to 25, 50 or even 100 railroad cars in length. The repair of a failed coupler knuckle can be labor intensive, can sometimes take place in very inclement weather and can cause train delays.
Coupler knuckles are generally manufactured from a cast steel using a mold and three cores. During the casting process itself the interrelationship of the mold and three cores disposed within the mold are critical to producing a satisfactory railway freight car coupler knuckle. Many knuckles fail from internal and/or external inconsistencies in the metal through the knuckle. If one or more cores move during the casting process, then some knuckle walls may end up thinner than others resulting in offset loading and increased failure risk during use of the knuckle.